Subduction zone studies: Sheehan is a PI on the Alaska Amphibious Array Community Seismic Experiment (AACSE) and the Hikurangi Ocean Bottom Investigation of Tremor and Slow Slip (HOBITSS) experiments. Both of these projects involved the deployment of ocean bottom seismic and pressure sensors to study subduction zone processes including slow slip, megathrust earthquakes, and tsunamis. Graduate students and postdocs on these projects have worked on seismicity, attenuation, and tomography.

Induced seismicity: Sheehan’s seismology group, in close collaboration with the hydrogeology group of Prof. Shemin Ge, also in the Department of Geological Sciences, and geodesist Prof. Kristy Tiampo (CIRES/ESOC/GEOL), has made numerous contributions in recent years to studies of human-induced seismicity. Sheehan’s group has an ongoing experiment in northeast Colorado and maintains a webpage with direct access to real time seismic data from throughout Colorado at earthquake.colorado.edu

Continental crust and mantle imaging: Sheehan’s group made many early contributions to the use of converted seismic wave imaging and anisotropy studies of the continental lithosphere. Current method development includes coda wave autocorrelation interferometry, with the goal of better utilizing short-term but dense deployments of seismometer, with targets including crustal faults at depth.

Tsunami studies: A recent focus of the Sheehan group is in tsunami studies. This grew out of Sheehan’s involvement with ocean bottom seismic experiments, and the recognition that tsunami signals were well-recorded on the pressure sensors associated with such deployments. This has led to productive collaborations with international researchers and new development of in-house expertise.

How do gas hydrates breathe? Insights from ocean-bottom seismometer observations